If your customer record has a mobile phone number you can send text messages directly from EQ. Your messages can use templates with merge fields. You can send individual texts or high volume marketing campaigns, all personalised with the aid of merge fields.
Ensure you have setup your text message settings and purchased credits in Tools > Customise > Text Messaging.
Sending 1 text costs 1 credit.
1.Open the customer window
2.Locate a customer
3.Click the 
Text (SMS) button
4.The To field will already have the customer's phone number completed but click To.. to add from other contacts who have a mobile number.
5.Type your text in the message box, up to a limit of 160 characters.
OR
Select a text template from the list or click 
Edit Popup Contents to amend/add a template.
6.Click Send